FIG. 1 relates to the present manner in which Voice Over IP (VoIP) communications are supported. VoIP, as is understood by those of ordinary skill, is a term of art that relates to the ability of an IP based packet network to support “real time” communications such as telephone conversations, video-conferences, etc. IP is an acronym for the Internet Protocol (IP). The IP protocol (of which various downward compatible versions currently exist and may be developed in the future) is a networking protocol that is used, in a sense, as a cohesive “glue” that communicatively couples smaller networks (which are often referred to as “subnets”) to one another. An IP subnet refers to a segment of an IP network. IP-based devices associated with the same subnet have the same network prefix; but are distinguished from one another with a different host ID within their respective IP addresses.
FIG. 1 shows a plurality of subnets 103, 104, 120, 123, 127 that are communicatively coupled to one another through the use of the IP protocol. Here, IP network 101 may be viewed as a larger network that is able to direct a packet from a first subnet (e.g., subnet 103) to a second subnet (e.g., subnet 104) based upon the IP destination address found within the header of the packet. Note that the path through the IP network 101 from one subnet to the other (e.g., from subnet 103 to subnet 104) may involve multiple hops through various networking hardware elements (such as switches and/or routers).
A VoIP server 102 is used to control and facilitate VoIP based communications. Here, the VoIP server 102 acts as a control station that: 1) “keeps track of” the VoIP devices that can entertain a VoIP connection through a registration process; 2) helps setup a connection between at least a pair of VoIP devices that seek to establish a VoIP connection (e.g., by way of providing various services such as authentication, address resolution, etc.); and 3) becomes one of the hops through which an established VoIP connection flows (better said, once the VoIP connection is established, the packets that carry the real time data (such as a digital representation of an individual's voice and/or a video image) pass through the VoIP server 102).
FIG. 1 can be used to explain the role of the VoIP server 102 in more detail. As alluded to above, VoIP devices (such as VoIP devices 108 and 109) should be registered with the VoIP server 102 prior to their engaging in a VoIP communication. A VoIP device is any device that can act as an endpoint (e.g., a source endpoint or a destination endpoint) for a VoIP connection. Some VoIP devices may be stationary or quasi stationary (such as a personal computer (PC) equipped with a working telephone); while, other VoIP devices may be more easily moved such as a handheld phone, a handheld personal digital assistant (PDAs), a handheld device that behaves as a combination of the two, a laptop computer, etc.
Through the registration process, a new VoIP device effectively identifies itself to the VoIP server 102 as a “new member” of the VoIP community that the VoIP server 102 acts to support. Here, FIG. 1 shows registration information 112, 113 being directed from each of the VoIP devices' 108, 109 respective subnets 103, 104 to the VoIP server 102. As a result of the VoIP server's reception of this registration information 112, 113, the VoIP server is able to develop an understanding of the location and capabilities of the new VoIP devices 108, 109; and, integrate this information into its current understanding of the collection of various VoIP devices it may be asked to help orchestrate a VoIP connection for.
After the VoIP devices 108, 109 have been registered, they can thereafter engage in a number of different VoIP connections. As an example of how a VoIP connection can be established and carried out, an initiating VoIP device (e.g., VoIP device 108) sends signaling information 114 to the VoIP server 102 that effectively informs the VoIP server of the other VoIP device (e.g., VoIP device 109) to which the initiating VoIP device 108 wishes to communicate with. In response, the VoIP server 102 resolves the address information for the called device and sends the signaling information 115 to the VoIP device 109 that acts as the recipient of the VoIP call; and, helps to establish the IP connection between the two VoIP devices 109. Once the connection is established, substantive data communications 114, 115 (e.g., in the form of one or more packets that carry real time information) between the VoIP devices 108, 109 flow through the IP server 102 in order to implement the call.
Note that in the exemplary depiction of FIG. 1, each of these VoIP devices 108, 109 are associated with a respective subnet 103, 104. Here, each subnet 103, 104 includes an IP gateway 107, 118 that is able to send and receive IP packets over a networking line 105, 106 (e.g., a copper or fiber optic cable). Each networking line 105, 106 couples its respective IP gateway 107, 118 to the IP network 101. Note that the hashed lines that couple each networking line 105, 106 to the VoIP server 102 within the IP network are drawn as such to indicate that multiple networking lines (e.g., via multiple hops through a plurality of routers and switches) may actually be used to reach the IP server 102 from a particular networking line 105, 106.